A phrase used to express how excited or mind-blown or confused you are feeling.

Snooter: Oh my GAWD!! That Inception movie was sooooo good.
Smitty: OMG, I had to watch it three times... I shit a brain the first time.

Snooter: Oh my GAWD!! That movie Memento was sooooo crazy.
Smitty: OMG, I had to watch it six times... I shit a brain the first five times.

Snooter: Oh my GAWD!! That movie Requiem for a Dream was sooooo intense.
Smitty: Uh... I actually had a seizure during that one. I shit my pants.
Snooter: For reals? Oh... my... gawd.
Smitty: yeah... flopped around for... well... through the rest of the movie, actually. My cat just watched me... he didn't call 911 or help out... so... I missed most of that movie. Not a big fan...